The invention relates to a power source element, such as a non-aqueous electrolyte cell capable of being mounted on a surface or an electric double layer capacitor making use of the electric double layer theory.
Non-aqueous electrolyte cells and electric double layer capacitors have been conventionally used as backup power sources for clock function, backup power sources for memories of semiconductors, standby power sources for electronic devices such as microcomputers, IC memories and the like, cells for solar watches, and electric power sources for driving of motors, and have been investigated as electric power sources for electric automobiles and auxiliary power storage units of energy transformation and storage systems in recent years.
For backup power sources, high capacity and electric current for driving of semiconductors have been hitherto needed. In recent years, however, semiconductor memories have been put into use, which have no need of backup power sources owing to improvements in the technology of nonvolatile memory. Also, low power consumption has been promoted in elements with clock function. Accordingly, there has been reduced the need for non-aqueous electrolyte cells and electric double layer capacitors, which require substantially large capacity and electric current.
A non-aqueous electrolyte cell or an electric double layer capacitor is constructed as shown in FIG. 2. A positive active material 201 is bonded to a positive electrode case 203 with an electrode collector 202 and negative active material 204 is bonded to a negative electrode case 205 with another electrode collector 202. The negative electrode case 205 is inserted into the groove for the gasket 207. With the electrolyte 206 added, the negative electrode case 205 and positive electrode case 203 are combined together and the positive electrode case 203 is crimped for sealing.
The need for non-aqueous electrolyte cells and electric double layer capacitors, which require substantially large capacity and electric current, has been reduced due to the fact that nonvolatile memories have prevailed and low power consumption has been promoted in elements with clock function. Rather, with respect to non-aqueous electrolyte cells and electric double layer capacitors, the demand has been increased for thinning of them and ref low soldering (a method of soldering, comprising beforehand applying a soldering cream or the like on those portions on a printed circuit board, which are to be subjected to soldering to place parts on the portions, or after such placing of parts, supplying small soldering balls (soldering bumps) to portions being subjected to soldering, and passing the printed circuit board with parts thereon through a furnace under high temperature atmosphere set so that portions being subjected to soldering become above the melting point of solder, for example, 200 to 230xc2x0 C., to thereby melt solder).
Since conventional non-aqueous electrolyte cells and electric double layer capacitors have a cross section shown in FIG. 2 to be circular like coins and buttons, reflow soldering entails the need of beforehand welding terminals or the like to a casing, with the result that the cost goes up in terms of an increase in the number of parts and in manufacturing manhour. Also, it is necessary to provide on the board a space for terminals, and so limitation is imposed on making the cells and capacitors small in size.
In a non-aqueous electrolyte cell and an electric double layer capacitor, which are composed of active materials used as a cathode and an anode, and a container for receiving the materials and an electrolyte, the container is composed of a concave-shaped container and a sealing plate.
The concave-shaped container is made of a good heat-resistant material such as heat resisting resins, glass, ceramics or ceramic glass, and a metallic layer is formed on the inner bottom surface of the concave-shaped container to make a first collector to be electrically connected to a joining terminal disposed on the outer bottom surface of the concave-shaped container.
Also, a metallic layer is formed on an edge of the concave-shaped container to be electrically connected to a joining terminal disposed on the outer bottom surface of the concave-shaped container. A cathode active-material, a separator, and an anode active-material, which are made to be sheet-shaped, are stackingly inserted in the concave-shaped container.
The joining terminals are formed on either the outer bottom surface and sides of the concave-shaped container or either of the outer bottom surface and sides in such a manner to eliminate short-circuiting.
Subsequently, a bonding material, such as a brazing material or a solder material, having a configuration substantially identical to that of the edge of the concave-shaped container is placed on the edge of the concave-shaped container to be interposed between it and the sealing plate. The sealing plate may be formed of a metal or a good heat-resistant material such as a heat-resistant resin with a metallic layer, glass, ceramics or ceramic glass or the like.
The sealing plate is heated to above the melting point of the bonding material, such as a brazing material or a solder material, and pressurized for sealing.
Since the joining terminals are made integral with the receiving container and disposed on a lower portion of the receiving container, it becomes possible to decrease space in the form of a sheet.
Thus, the invention provides a non-aqueous electrolyte cell and an electric double layer capacitor, which are composed of active materials used as a cathode and an anode, and a container for receiving the materials and an electrolyte. The container comprises a concave-shaped container and a sealing plate, and the concave-shaped container is provided on an inner bottom surface thereof with a first collector which is electrically connected to a joining terminal disposed on an outer bottom surface and/or sides of the concave-shaped container. The sealing plate is provided on a surface inside the cell with a second collector which is electrically connected to a joining terminal disposed on an outer bottom surface and/or sides of the concave-shaped container. In this case, the sealing plate on the second collector is electrically connected to a joining terminal through the metallic layer on the edge of the concave-shaped container and bonding material.
Also, the first collector and the joining terminals disposed on the concave-shaped container of the receiving container and the metallic layer on the edge of the container are composed of a material having a main component which is a metal selected from tungsten, nickel, silver, platinum or gold.